Are you talking aout the breaker on the pedestal and is it good? If so you need to start by checking both ends of your shore cord and work your way back into the rig from there. Once you lost the 110 you drained your battery assuming it was good and that cut your 12v.

Thanks for all of the help ,YES I checked both ends of power cord all is good,the breaker will not stay engaged, I don't have a fuse by the battery all of my fusses are inside by the voltage regulator .
I made a mistake there is a fuse next to battery it is good ,I also checked wiring from HOT water heater to breaker panel

I would turn off all breakers in the trailer. Then reset the park breaker (assuming that is the one tripping). Then one by one turn the trailer breakers back on, starting with the main breaker, until the park breaker trips again. That should at least give you a starting point for troubleshooting.

In all the conversation, I have yet to see the answer about what breaker tripped. Was it a 120 v breaker? or a 12 volt DC breaker, like what would be at the battery feeding the main 12 volt circuit to the rig's electric panel? If there is a 12 volt auto reset breaker at the battery, it is very possible that if that failed completely, you would have no 12 volts to your panel and your converter could not charge your battery. Make sure we are talking apples and oranges here. Most of the time, breakers are 120 volts AC, like what comes from the pedestal through the shore cable. Except for the 12 volt auto reset breakers, all 12 volt DC is usually protected by fuses. Also, do you have a battery disconnect switch on this rig? And, if so, is it turned on? The ones installed on these rigs, when the circuit is connected, the red plastic key can not be removed, and if the circuit is disconnected, the key can be removed. If the disconnect switch has the circuit open, your battery will not be connected to the converter and the battery will become discharged, no 12 volts.

Hello rohrman it is 120v,not sure what 12v auto reset breaker looks like. I have a fuse about 10inchs
From battery. I have checked all of the fusses there
Good. I talked to a service rep he said maybe HOT
Water element ?.

There have been numerous reported issues in the Relay box mounted on the back corner of the Hot Water Heater. The switch inside the RW that's labeled for the Electric Hot Water supplies only 12VDC to the relay box on the heater. That relay is what connects the 120VAC to the heater. Mfrs have been doing a poor job of connecting the leads using wire nuts. I had a poor connection that melted the wire nut and then shorted to ground tripping the heater's breaker. Something to look into.

Just had this happen to my RV. I have a Montana, 3810, 50 amp. Called rv park. Turns out there was a loose hot wire on the back of the park electric pole. The mechanic tightened the hot wire of the 50 amp circuit bracker on the pole and all is good.